This invention relates to what are referred to herein as line markers, of the type that are mounted on a suspended line, such as a suspended power line, to provide a conspicuous body relatively easily seen by pilots operating aircraft whereby a collision with the power line may be avoided.
Power transmission lines are increasingly found throughout the United States as the practice of transporting electrical power over substantial distances to different regions becomes more common. Power lines employed typically are suspended from spaced towers, and in many instances, as when the lines extend across a canyon, river, or the like, may have substantial elevation over the ground with .the towers supporting them being spaced widely apart. Because of these and other factors affecting visibility, the lines represent a hazardous condition for aircraft. To reduce the hazard involved, so-called line markers have been devised which are suspended on a power line to be carried by it, and which, by reason of their size and/or color, provide a conspicuous marking alerting aircraft operators to the presence of the lines.
Mounting of a marker on a power line presents its problems because of the suspended nature of the line with which it is to receive the marker, the bulk of the marker (which makes it difficult, in many instances, to reach behind it from one side of the marker), and the number of loose parts which in the past have been required to perform the mounting operation. In general terms, this invention concerns a unique marker (and method of installation) which is readily installed from essentially one side of the marker only, and with installation performed with a minimum of number of loose parts. With the line marker contemplated, the marker may be installed utilizing, for instance, a platform suspended from a helicopter to support the workman performing the installation, with essentially a single positioning of this platform.
An object of the invention, therefore, is to provide an improved line marker which is installable on a line, such as a suspended power line, by a workman positioned in the air and on one side of the marker.
Another object is to provide a line marker which includes mating sections which envelop the line after mounting of the marker, and which are interconnected in clam-shell fashion, with the sections having limited separability in a region opposite their interconnection to accommodate the mounting operation.
In a preferred embodiment of the invention, the line marker includes a pair of oppositely disposed marker halves or sections where the halves have the same size and shape and take the form of hemispheric shells. Prior to mounting and on the ground, the hemispheric shells are secured together with the shells facing each other and open ends in registry, in a region located on one side of a passage which is defined extending between the shells for receiving the line. The shells are made of a stiff, but flexible plastic material, and when so connected, and by reason of the plastic nature of the shells, may be flexed away from each other in a region opposite the region where they are joined. Mounting of the marker is effectuated by so flexing the shells, in clam-shell fashion, and from a work station located adjacent the suspended line. One or more anchor assemblies, each of which includes a base and a length of wire extending from the base, are mounted on one or both of the shells through securement of the base described to a shell with the wire length extending outwardly from the shell. Mounting of a marker is completed by completely securing the halves described together, and by connecting, as by wrapping, the length of wire in an anchor assembly about the line, which has the effect of preventing movement of the marker axially on the line.